The objectives of this project are (1) to assess psychophysical methods of experimental pain measurement, i.e., magnitude estimation, category scaling, and cross-modality matching. Pain will be experimentally induced by electrocutaneous, electric tooth pulp, and mechanical heat stimulation; (2) to assess clinical pain measures, such as pain questionnaires and sensory matching methods, in a dental setting; (3) to determine the validity of experimental pain models by comparison of experimental and clinical pain responses; and (4) to evaluate known pharmacological and non-pharmacological pain-control agents. The interactive computer-based scaling method was used to assess the relation between analgesia time course and fentanyl dose. Fentanyl produced analgesia peaking at 11 min post infusion that was greater with increasing stimulus temperature and fentanyl dose. Rate of analgesia onset was not dose dependent. A second study using the interactive scaling method showed that the method was sensitive to changes in response range but not to increases in overall stimulus intensity. Reliability of the alternative forms of the Descriptor Differential Scale was reassessed in a cross-validation study. Preliminary results show reliabilities (r = .8) similar to those found in the first study. A study of hypnotic analgesia showed that the cold-pressor pain measure, which is very vulnerable to response bias, shows significantly greater analgesia than the interactive scaling method. Thus, previous results may reflect partially response changes unrelated to analgesia. A study showed that hypertensive subjects are relatively pain-insensitive, suggesting that hypertension may prove to be a maladaptive attenuation of stress-related distress. An initial study of pediatric pain showed that systematic physician ratings of patient pain can be used to continuously adjust the rate of continuous morphine infusions to provide adequate pain control with minimal side-effects.